Acetylenic amides



United States Patent '0 Ser. No. 234,254

1 Claim. (Cl. 260561) This application is a division of our copendingappli cation, Serial No. 90,209, filed February 20, 1961.

This invention relates to aceylenic nitrogen compounds and to improvedmethods of preparing such compounds.

Although procedures are known for the preparation of nitrogen compoundsof the acetylene series, i.e., nitrogen compounds having tripleunsaturated carbon linkages, by the reaction of amines, acetylene andaldehydes, such procedures have not, in general, proved commerciallyfeasible. The yields in these prior arts methods, for example, tend tobe low, and, moreover, because of the nature of the prior art reactions,side products and byproducts .are formed to a considerable extent, andgreat difficulty is experienced in recovering the desirable reactionproducts.

According to the teachings contained herein, com- -mercially feasibleprocedures for preparing nitrogen com- Still further in accordance withthe present invention there have been prepared dipropargyl amines of theformula:

RN CH-CEOH (12 2 In Formulae 1 to 3, inclusive, R may be an aliphatic,aryl, alkyl aryl or alicyclic hydrocarbon radical; R' may be analiphatic, aryl, alkyl aryl or alicyclic hydrocarbon radical orhydrogen; or the part may represent a heterocyclic base, namely,piperidine, morpholine or-pyrrolidine.

When R and R are hydrocarbon radicals, these will usuallyhave fewer than20 and preferably fewer than carbon atoms in the chain. Typically, R andR' may he aliphatic hydrocarbon radicals, such as propyl, isopropyl,n-buytl, isobutyl, tertiary butyl, hexyl, 2-ethyl hexyl, isononyl,n-nonyl, 3,5,5-trirnethyl pentyl, 1,1,3,3-tetramethylbutyl, and thelike, including the isomeric alkyl derivatives thereof. R and R may alsobe alicyclic hydrocarbon radicals, such as cyclopentyl, cyclohexyl,cycloheptyl, cyclooctyl, and so forth. When R and R are aryl or alkylaryl groups, these may have one or more uncondensed benzene nuclei.Preferably, however, R

3,263,583- Patented August 23, 1966 "Ice and R have one uncondensedbenzene'nucleus. Typical of such groups may be mentioned phenyl and itshomologues, such as tolyl, xylyl, and so forth.

In Formulae 1 to 3 above, K" may be hydrogen or a lower alkyl radicalhaving up to 6 carbon atoms. Usually R" will be hydrogen, as will beclear from the following description.

As will be more clear from the following description, the groups R, R,or the part in the above formulae will correspond to the radicals makingup the primary or secondary amines or cyclic imines used to prepare theacetylenic nitrogen compounds. The group R" will correspond to thehydrocarbon radical making up the carbonyl compounds used in thereactions, or hydrogen.

These and other amino compounds of the acetylene series, i.e., aminocompounds having triple unsaturated carbon linkages, have been preparedby reacting amines, including cyclic imines, having at least one activehydrogen attached to the amino nitrogen, aldehydes, and acetylene in aninert reaction medium and in the presence of catalysts.

Typical reaction mechanisms for the compounds represented in Formulae 1to 3, inclusive, may be represented as follows:

As catalysts suitable for carrying out the above reactions may bementioned the heavy metals of subgroups I-B and II-B of the PeriodicTable of Elementsand their compounds, as, for example, organicandinorganic salts of copper, such as the chloride, acetate,formate,,and,so forth. Also may be mentioned the ,acetylides of suchheavy metals, for example, acetylene-copper compounds. Other catalysts,such as Adkins catalyst, i.e., :copperbarium chromite, may also be used.Among the; catalysts, the copper salts, and more particularly the cupricsalts, are especially suitable. Particularly goodresults are obtainedwith cupric chloride, and this ;material -.is preferred.

The catalyst or mixtures thereof may, if desired, be used with suitableinert carriers, such as, for example, finely divided alumina,diatomaceous ,earth, silica, ,silica gel, kieselguhr, and mixtures ofthe foregoing.

Primary and secondary amines, as well ascyclic imines, and mixtures ofthe foregoing, areusefulin preparing the acetylenic amino compoundsdescribed herein. :When aliphatic amines are used, these may be primaryor secondary amines having straight chains orbranched chains typified bythe following: methyl, ethyl,1propyl, isopropyl, nbutyl, isobutyl,tert.-butyl, hexyl, 2-ethylhexyl, isononyl, n-nonyl,3,5,5-trimethylpentyl, 1,1,3,3-tetramethylb utyl groups and the isomericalkyl derivatives thereof. When secondary amines are used, thehydrocarbon radicals attached to the amino nitrogen may be the same ordifferent. As will be clear from the examples, best results are achievedwith the sec-ondary amines. As examples of the saturated monocyclicheterocyclic amino compounds, or, more properly, cyclic imines, may bementioned morpholine, piperidine and pyrrolidine. Both primary andsecondary aryl or alkyl aryl amines may be used, depending upon the typeof acetylenic amino compounds desired. Of the aryl compounds, thearomatic amines having a single benzene nucleus are preferred. Amongthese may be mentioned aniline, toluidine, xylidine, and the mono-alkylderivatives thereof, such as monomethyl aniline, monoethyl aniline, andother mono-alkyl phenyl amines having up to about carbon atoms in thealkyl group. Typical of the alicyclic amines may be mentionedcyclopentylamine, cyclohexylamine, cycloheptylamine, cyclooctylamine,and so forth. Also may be mentioned the mono-substituted alicyclicamines, such as cyclopentyl ethyl amine, cyclohexyl methyl amine, and soforth. When primary and secondary amines are used, these preferably havefewer than a total of carbon atoms. Other suitable amines and cyclicimines will readily suggest themselves to those skilled in the art fromthe foregoing description.

The reaction of the above described amino nitrogen compounds withacetylene and aldehydes is carried out in an inert solvent medium. Careshould be exercised in selecting the solvent to prevent undesirableby-product and side-product formation and to avoid tedious recoveryprocedures. It has also been discovered that the choice of reactionmedium has a significant effect on the yields achieved.

In general, non-polar solvents which are inert to both the startingmaterials and the reaction products and which are readily volatilizablemay be used. Among such solvents, saturated or unsaturated aliphatichydrocarbons which are liquid at atmospheric conditions are especiallysuitable. Preferred for use are saturated aliphatic hydrocarbons having6 to 19 carbon atoms.

The aldehydes suitable for use in the present invention may be describedas simple aldehydes having one carbonyl radical. Although carrying outthe reaction with aldehydes containing more than 1 carbonyl radical isfeasible, in general, the use of such materials causes undesirable sidereactions. Among the particularly important aldehydes may be mentionedformaldehyde, including formalin (an aqueous solution of about 37percent by weight of formaldehyde) and methyl Formcel (a solution ofabout percent by weight of formaldehyde in methanol), acetaldehyde, andother simple aldehydes having fewer than about 6 carbon atoms. Theprecursors of formaldehyde, e.g., the cyclic trimer known as trioxan,and the linear polymers of formaldehyde, known as polyoxymethylenes, asWell as the cyclic polymer of acetaldehyde, known as paraldehyde, may beadvantageously employed.

Although any of the above described aldehydes may be used, it has beendiscovered that greatly superior results are obtained in preparingcompounds :of the Formulae 1 to 3 described hereinabove when linearpolymers of formaldehyde are used. Such polymers are polyoxymethylenesof the formula where n is an integer up to 100. Especially good resultsare obtained when trioxymethylene, which is commonly referred to asparaformaldehyde, is employed, and this material is preferred.

The acetylene used in the reaction may be highly concentrated acetylene,or acetylene dilutedwith foreign gases which are inert to the reaction.Electric arc acetylene, for example, may be used.

The method of contacting the reactants is important. Thus, it has beendiscovered that greatly improved yields are obtained by suspending thealdehyde in an inert nonpolar solvent containing the catalyst,subjecting this reaction medium to an atmosphere comprising acetylene,and adding the amine to the resulting environment.

Care should be taken in adding the amino nitrogen compound to avoid thepresence of excess unreacted amino nitrogen compound in the reactionmedium. Thus, too rapid an addition of the amino nitrogen compoundresults in decreased yields of desirable products and production ofby-products, side products and tars. The rate of addition of the aminonitrogen compound should be slow enough so as to avoid the presence ofexcess unreacted amine in the reaction mixture. In general, the rate ofaddition of the amine should be such that at any given time less thanabout 25 mole percent, and preferably less than about 10 mole percent ofunreacted amino nitrogen compound is present in the reaction mixture,based upon the moles of unreacted aldehyde in the reaction mixture. Therate of addition of the amine, in terms of moles of amino nitrogencompound per minute per mole of aldehyde in the reaction mixture, mayvary between about 0.0005 and 0.15, is usually between about 0.005 and0.015, and is preferably between about 0.0025 and 0.030.

The proportion of amine to aldehyde is also important. In general, themolar ratio of amine to aldehyde may vary between about 0.80 and 1.20:1and is preferably between about 1.0 and 1.10:1. When polymers of thealdehydes are employed, the above described molar ratios are based uponmoles of equivalent aldehyde and not moles of the polymers. Whenparaformaldehyde is used, for example, a molar ratio of amine toparaformaldehyde of betwen about 1.0 and 1.10:1 is preferred, and amolar ratio of about 1.05:1 is optimum, the molar ratios being based onHCHO.

If desired, the reaction may be carried out under anhydrous conditions,and in some instances, this may be preferable. Any suitable dehydratingagent which is inert to reactants and to the products of reaction may beused to take up the water produced by the reaction. Such dehydratingagents are well understood in the art. As a typical example may bementioned anhydrous sodium sulfate.

The temperature and pressure of reaction should be high enough to causereaction to occur, but below the temperature and pressure at which tarand undesirable side products and by-products form. The temperature ofreaction may vary between about 40 C. and C., or higher, and ispreferably between about 50 C. and 60 C. At the lower part of the range,the reaction appears to be sluggish, while at the upper part of therange, secondary products, as well as side products and tars, tend toform. Although the reaction may be carried out at pressures betweenabout 2 and 40 atmospheres, reaction pressures of between about to 250p.s.i.g. are especially advantageous, and are preferred.

The invention will be more fully understood from the following examples,which, although illustrative, are not intended to limit the scope of theinvention, except as such limitations may appear in the claim.

EXAMPLE 1 The reactor comprises a one-liter, upright, stainless steelautoclave equipped with an agitator, thermocouple well, acetylene gasburette, liquid amine burette, a proportioning pump for the liquid amineburette, and a pressure regulator for the acetylene gas burette.

Seventy-five grams of anhydrous n-hexane, 59.4 grams of paraformaldehyde(90% trioxymethylene), which have been desiccated over sodium hydroxidepellets, and 6.02 grams of anhydrous powdered cupric chloride arecharged to the autoclave liner. The autoclave is assembled, and pressuretested by purging with nitrogen. The system is then purged withacetylene, bled off to 25 p.s.i.g., and then heated to 60 C. Acetyleneis then added to bring the pres-sure up to 150 to 175 p.s.i.g. andmaintained at this pressure throughout the reaction by means of the gasburette and pressure regulator. The acetylene used is purified bypassing it through a Dry Ice trap and activated alumina.

Diethylamine having a boiling point of 55 to 56 C. at 1 atmospherepressure is charged to the amine burette. The diethylamine is added tothe reaction mixture in the autoclave over a period of about three andone-half hours at a uniform rate of about 0.65 gram/minute. Theproportioning pump is used to insure a uniform rate of addition. Thetotal charge of diethylamine is 137.2 grams. At the completion of theamine addition, the reaction is continued until no more acetylene istaken up. This point is reached approximately one hour after completionof the diethylamine addition. The mixture is then cooled and dischargedfrom the autoclave.

The mixture is filtered through a medium sintered glass Buchner funnel.The small filter cake obtained is Washed once with a small portion ofn-hexane and the filter cake is discarded. Caution is necessary toinsure that the filter cake is not allowed to dry. After washing, dilutehydrochloric acid is added immediately to destroy any copper acetylidepresent.

A small water layer which appears in the filtrate is separated anddiscarded. It Weighs about 33.4 grams and contains 5.0 percent by weightof diethylamine.

The hexane layer is then distilled through a small Vigreux column underreduced pressure with the pressure being lowered gradually as thedistillation progresses. A nitrogen atmosphere is maintained during thedistillation. The distillation data are tabulated in Tables I to III.

Cut Cis mainly bis(diethylamino)butyne.

Cut A is next fractionated through a small packed column starting atatmospheric pressure and maintaining a nitrogen atmosphere.

Table II Pot Head Press, Temp., Temp, mm. Cut:

1 atm. Cut; 1, water layer, 4.4 g.; organic layer, 131.5 g. (contains4.7% diethylamine).

Cut B above is added to the still pot and the distillation resumed underreduced pressure.

Table III Pot 'Head Press, Temp., Temp., mm. Gut

41-58"-.. 38-50 75 Cut 2 7.4 g. (64.0% propargyl diethylamine 58-9654-58 75 Out 3, 164.6 g. (97% or higher propargyl diethylamine) Potresidue (orange liquid), 2.2 g.

The percent conversion of the diethylamine to acetylenic amines is 90.1%of theoretical. Of this conversion, an 83.0% yield of propargyl diethylamine and a 7.1% yield of bis(diethylamino)butyne are achieved. The

amount of diethylamine recovered indicates that the diethylamine hascombined in practically stoichiometric proportion-s with theparaformaldehyde, i.e., the amine recovered is about equal to the molarexcess of diethylamine added, based on the paraformaldehyde.

EXAMPLE 2 For comparison purposes, Example 1 is repeated, with theexception that formalin (a 37% by weight aqueous solution offormaldehyde) is used in place of the n-hexane and paraforinaldehyde.The yield of propargyl diethylamine is 59.5% of theoretical, and theyield of bis(diethylamino)butyne is 6.1% of theoretical, for a totalyield of acetylenic amines of 65.6%, which is considerably below thatobtained in Example 1.

EXAMPLE 3 For comparison purposes, Example 1 is repeated, with theexception that methyl Formcel (a 55% solution of formaldehyde inmethanol) is used in place of n-hexane and paraformal-dehyde. Otherconditions are identical to those of Example 1. A 49.5% conversion toamino propyne and a 2.3% conversion to diamino butyne are achieved.

EXAMPLE 4 Example 1 is repeated, with the exception that the ratio ofdiethylamine and paraformaldehyde to n-hexane and catalyst was doubled.Yields comparable to those of Example 1 are obtained.

EXAMPLE 5 Example 1 is repeated, with the exception that dibutylamine issubstituted for diethylamine. Yields of propargyl dibutylamine andbis(dibutylamino)butyne comparable to the yields indicated in Example 1are obtained.

EXAMPLE 6 Example 1 is repeated, with the exception that dimethylamineis substituted for diethylamine. Yields of propargyl dimethylamine andbis(dimethylamino)butyne comparable to the yields indicated in Example 1are obtained.

EXAMPLE 7 Example 1 is repeated, with the exception that the cyclicimine, morpholine, is substituted for diethylamine. Yields of 8.3%bis(rnorpholino) butyne and 72.6% of N- propargyl morpholine, for atotal yield of 80.9% of acetylenic amino compounds, are achieved.

EXAMPLE 8 Example 1 is repeated, with the exception that pyrrolidine issubstituted for diethylamine. Yieldsof bis(pyrrolidino)butyne andN-propargyl pyrrolidine comparable to the yields indicated in Example 7are achieved.

EXAMPLE 9 Example 1 is repeated, with the exception that piperidine issubstituted for diethylamine. Yields of bis(piperidino)butyne andN-propargyl piperidine comparable to the yields indicated in Example 7are achieved.

EXAMPLE 10 mary amines reacted poorly; under other conditions reactionsof primary amines with acetylene are quite good, but the desiredproducts, although apparently formed, appear to condense or polymerizeto high boiling products.

In spite of the foregoing, it has been discovered that an excellentreaction occurs when primary amines, carbonyl compounds and acetyleneare reacted under the conditions described hereinabove in connectionwith the secondary amines. The reactions with the primary amines areslightly more exothermic and acetylene uptake is more rapid. Incomparison with the secondary amines, reduced conversions are obtainedwith the primary amines.

EXAMPLE 11 Using the conditions of Example 1, n-butyl amine, acetyleneand paraformaldehyde are reacted in the presence of cupric chloride,using a n-hexane reaction medium. Hexane in the amount of 150 grams,paraformaldehyde in the amount of 59.4 grams, and cupric chloride in theamount of 60 grams are added to the autoclave. Normal butyl amine in theamount of 142 grams is added to the resulting mixture at a uniform rateof about 0.79 gram/minute by means of a proportioning pump over a periodof about six hours. Reaction temperature and pressure are the same as inExample 1. The reaction mixture is worked up in the manner of Example 1.The main reaction product is dipropargyl n-butyl amine. The yield ofthis material is 24.0%. Small amounts of monopropargyl n-butyl amine arealso recovered.

EXAMPLE 12 Example 11 is repeated, with the exception that tertiarybutylamine is substituted for n-butylamine. Good yields of monopropargylt-butylamine and dipropargyl t-butylamine are obtained.

Under the conditions for preparing propargyl amines describedhereinabove, a small yield of corresponding secondary products, i.e.,diamino alkynes, are ordinarily produced. In the formation of propargyldiethylamine in Example 1, for instance, the secondary product is1,4-bis (diethylamino)-2-butyne. The procedure described herein may bemodified to specifically prepare diamino alkynes in high yields. Thereaction is carried out in two steps: First, propargyl amine isprepared, for example, using the procedure of Example 1. Then, theacetylene atmosphere is removed, additional aldehyde is charged to thereactor, and the second step is completed by addition of a secondportion of the amine, using the same conditions as employed in the firststep of the reaction. The reaction proceeds stepwise according to thefollowing equations:

As will be noted, acetylene is a reagent only in the first step.

EXAMPLE 13 Following the procedure of Example 1, diethylamine is addedto a reaction mixture of paraformaldehyde, acetylene, n-hexane andcupric chloride catalyst. When no further acetylene is taken up, theacetylene atmosphere is removed and an additional charge of 59.5 gramsof paraformaldehyde is charged to the reactor. An additional 137.2 gramsof diethylamine is then added to the reactor at a uniform rate, which iscontrolled by the proportioning pump. It should be noted that in thisprocedure, acetylene is a reagent only in the first step.

The reaction mixture is worked up following the procedure described inExample 1. The conversion to 1,4- bis(diethylamino)-2-butyne iscomparable to the yield of propargyl diethylamine achieved in Example 1.

EXAMPLE 14 Example 13 is repeated, with the exception that morpholine issubstituted for diethylamine. Comparable results are achived, the mainproduct being l,4-bis(morpholino)-2-butyne.

The acetylenic amines are useful as intermediates in preparing othernitrogen compounds. According to another embodiment of the presentinvention, new and useful N acetylenic amides have been prepared, usingamino alkynes, which have been prepared, for example, by the method ofExample 11 or by other methods well known in the art, See, for example,Gardner et al., Journal of the Chemical Society, 1948, 780.

Acetylenic amides of the formula have been prepared where R and R aremembers of the group consisting of aliphatic, alicyclic, aryl, andalkyl-aryl hydrocarbon radicals of the type described hereinabove inconnection with the acetylenic amino compounds, and R" may be a loweralkyl having up to about 6 carbon atoms and may also be hydrogen.Usually, R and R in Formula 4 will have fewer than 20 carbon atoms, andpreferably they will have fewer than 10 carbon atoms.

Compounds corresponding to Formula 4 have been prepared by the reactionof amino alkynes having an active hydrogen attached to the aminonitrogen and corresponding to the formula with acid halides or acidanhydrides. R and R" in Formula 5 correspond to the radicals describedin connection with Formula 4. Typical of the acid halides that may beused are the acid fluorides, chlorides, bromides, and iodides of aceticacid, butyric acid, propionic acid, benzoic acid, toluic acid, alicycliccarboxylic acids, such as the carboxylic acid of cyclopentane, and soforth. Among the acid anhydrides may be mentioned acetic anhydride,phthalic anhydride, and the like.

The reaction is preferably carried out at temperatures below roomtemperature, or below about 20 C., preferably between about 0 and 20 C.Any suitable organic solvent may be used as the reaction medium. Typicalof such solvents are aromatic and aliphatic hydrocarbons. Such sloventsare well understood in the art, and any of the conventional solvents maybe used so long as they are inert to the reactants and products ofreaction.

EXAMPLE 15 The compound 3-(n-butylamino)-1-butyne is prepared in amanner well known in the art by using the following procedure:n-butylamine (103 g.), tetrahydrofuran (225 cc.) and cuprous chloride(10 g.) are treated at 106 C. with a mixture of acetylene and nitrogen.The reaction is continued until no further acetylene is taken up and theproducts of reaction isolated in the manner described in Example 1. Thereaction product contains g. of 3- (n-butylamino)-l-butyne having aboiling point of 76 to 79 C./65 mm., and a refractive index ofn =1.4388.

A reactor flask is equipped with a stirrer, thermometer, droppingfunnel, condenser, cooling bath, and a T-joint for maintaining anitrogen atmosphere.

Benzene (100.0 ml.) and acetyl chloride (17.2 g.) are placed in thereactor and cooled to between 10 and 15 C.

Twenty-five grams of the 3-(n-butylamino)-1-butyne prepared as above areadded to the flask dropwise over a period of one hour. Still maintainingthe temperature at 10 to 15 C., 25.3 grams of triethylamine are addedover a period of about 45 minutes to neutralize by-product hydrogenchloride. Following addition of the triethylamine, the reaction mixtureis stirred for about one hour.

The mixture is filtered, and the triethylamine hydrochloride filter cakeis Washed with small portions of benzene.

The filtrate is distilled under reduced pressure to obtain 25.8 grams of3-(N-n-butyl-N-acetylamino)-1-butyne; B.P. 66-67 C./0.35 mm., r1 1.4639.The percent conversion of 3-(n-butyl-amino)-1-butyne to 3-(N-n-butyl-N-acetylamino)-1-butyne is 75 percent of theoretical. The C=CHanalysis of the product was 15.0 percent (theory: 14.95% The productcorresponds to the formula:

CHgCHCECH CHaCHzCHzCHzNC O CH:

EXAMPLE 16 Normal butylamine is reacted with acetylene andparaformaldehyde according to Example 11 to produce a small amount ofmonopropargyl n-butyl amine.

Example 15 is repeated with the exception that monopropargyl n-butylamine is substituted for the S-(n-butylamino)-1-butyne. Comparableyields of 3-(N-n-butyl- N-acetylamino)-1-propyne are achieved.

EXAMPLE 17 Aniline is reacted with acetylene and paraform-aldehydeaccording to Example 11 to produce a small amount of monopropargylaniline.

Example 15 is repeated, with the exception that monopropargyl aniline issubstituted for 3-(n-butyl-amin0)-1- butyne. Comparable yields of3-(N-phenyl-N-acety1- amino)-1-propyne are achieved.

EXAMPLE 18 Example 15 is repeated, with the exception that benzoylchloride is substituted for acetyl chloride. Comparable yields of3-(N-n-butyl-N-benzoylamino)-1-butyne are obtained.

EXAMPLE 19 Cyclopentylarnine is reacted with acetylene andparaformaldehyde according to Example 11 to produce a small amount ofmonopropargyl cyclopentylamine.

Example 15 is repeated, with the exception that monopropargylcyclopentyl amine is substituted for 3-(n-buty1- amino)-1-butyne. Acomparable yield of 3-(N-cyclopentyl-N-acetylamino)-1-propyne isachieved.

The acetylenic amino nitrogen compounds described herein are valuableinitial materials for the preparation of solvents, pharmaceutical anddyestuffs. By themselves the acetylenic amino nitrogen compounds areeffective corrosion inhibitors. Condensation products made there fromare useful as pickling inhibitors, and the materials themselves may alsobe used as high energy fuels.

The acetylenic amides described herein are by themselves importantcorrosion inhibitors.

The invention in its broadest aspects is not limited to the specificcompositions, steps and methods described, but departures may be madetherefrom within the scope of the accompanying claim without departingfrom the principles of the invention and without sacrificing its chiefadvantages.

We claim: A compound of the formula -CHCECH RNCOR1 wherein R is a cyclicsaturated hydrocarbon group of 5 to 8 carbon atoms, R is an alkyl groupof at most 10 carbon atoms, and R" is a member selected from the groupconsisting of lower alkyl groups of up to 6 carbon atoms and hydrogen.

References Cited by the Examiner UNITED STATES PATENTS 2,546,762 3/1951Long 260558 3,078,275 2/1963 Mofiett et a1. 260558 FOREIGN PATENTS917,424 9/1954 Germany.

OTHER REFERENCES Hennion et al.: Jour. Am. Chem. Soc, vol. 75, p.1653-1654 (1953).

Marszak-Fleury: Annales die Chemie, v01. 13, N0. 3, p. 671 (1960).

Noller: Chemistry of Organic Compounds, 2nd ed., 161-63, 237, and 244,Philadelphia, Saunders, 1957.

Shriner et al.: The Systematic Identification of Organic Compounds, 3rded., pp. 177-78, N.Y.. 1948. Wiley.

WALTER A. MODANCE. Primary Examiner.

NICHOLAS RIZZO, Examiner.

NATALIE TROUSOF, R. L. PRICE,

Assistant Examiners.

